Can You Freeze Rosemary?

More rosemary than you can use? It’s one of the herbs the sources single out for the freezer: you can freeze it right on the stem,¹ and America’s Test Kitchen says sturdy herbs like rosemary, sage and thyme make the best herb ice cubes.² A small Italian study even found that frozen rosemary held on to its essential oil better over nine months than air-dried or freeze-dried rosemary.³ It softens when it thaws, so use it in roasts, braises and stews, and for the best quality, within 3 to 6 months.⁴

At a glance

Question	Short answer
Can it be frozen?	Yes. Penn State notes rosemary can even be frozen on the stem.¹
Best methods	Whole sprigs on a tray, then bagged; or chopped leaves in ice cube trays under water or oil.
Freezer temperature	0°F or below.⁴⁵
How long	For best quality, 3 to 6 months (Ohio State). Other figures below.
Thaw first?	No. Add it frozen to cooked dishes.
Oil cubes	Keep them frozen; once thawed, refrigerate and use within 4 days.⁶

How to freeze rosemary

Prep it. Rinse the sprigs, then pat or spin them dry. Freeze rosemary at peak freshness.

Method 1: whole sprigs, tray-frozen. You can freeze rosemary right on the stem.¹ Spread the well-drained sprigs in a single layer on a tray and freeze until firm, then move them to labeled bags or containers, pressing out as much air as you can before sealing. Freezing them spread out first keeps them from fusing into one clump, so you can pull out a single sprig. Once they’re frozen, the needles strip right off the stem.

Method 2: ice cubes. America’s Test Kitchen chops the herbs, puts 2 tablespoons in each well of an ice cube tray, covers them with water or oil, and freezes them, then moves the cubes to a zipper-lock freezer bag. ATK suggests oil cubes to start a sauté and water cubes for pan sauces, soups and stews.² Penn State’s one caution: herbs frozen in cubes cook unevenly as the cube melts.¹

Method 3: in oil. Penn State’s ratio for herbs in oil is about ⅓ to ½ cup of oil to 2 cups of chopped herbs, frozen in cube trays, small jars, or flat in a zip-top bag. Only add oil to herbs you’re going to freeze.¹

Label and date the bags. Rosemary smells strong, so Penn State suggests double-wrapping strong-smelling herbs in foil or using airtight glass jars to keep the smell from spreading to other food.

How long frozen rosemary keeps

Source	What it covers	Figure
Ohio State University Extension⁴	Frozen herbs, best quality	Use within 3 to 6 months; may be safe after a year or longer
Usai et al., 2009³	Rosemary frozen and held at -18°C, tested every 3 months	Smallest essential oil loss of the three methods over 9 months; no shelf-life figure
Colorado State University Extension⁵	Frozen vegetables in general, at 0°F or below	High quality for 12 to 18 months; no figure given for herbs
USDA freezing fact sheet⁷	Frozen food in general	Safe almost indefinitely; storage times are for quality only

You’ll see figures like “good for about a year, best within three months” for frozen rosemary, but we couldn’t trace either number to a named source. The sources above don’t really contradict each other. They answer different questions: Ohio State gives a quality window for herbs, Colorado State’s figure is for vegetables, and the USDA fact sheet is about safety.

What the research shows

The only study we found that froze rosemary and tracked it over time comes from Sardinia. Researchers split fresh rosemary and thyme into batches that were air-dried, frozen or freeze-dried, stored them for nine months, and analyzed the volatile oil every three months. The frozen herbs were packed in polyethylene bags and kept in the dark at -18°C.

For rosemary, essential oil yield dropped most in the freeze-dried samples, and the frozen samples lost the least.
The authors concluded that freezing was the best way to stabilize both herbs, and called their results preliminary.³

It’s a short conference-style report. It names the compounds that changed but gives no yield figures, and nobody tasted anything. So it backs freezing as the best way to hold rosemary’s oil, but it won’t tell you how long frozen rosemary stays good.

Freezing still changes the leaf. The water in the leaves expands as it freezes, which is why thawed herbs go limp.¹ Herbs frozen in oil hold their color better than herbs frozen plain.

Food safety

Rosemary in oil. Low-acid foods like herbs, stored in oil, sit in an oxygen-free environment. Oregon State explains that these mixtures have to be stored correctly to prevent botulism, caused by Clostridium botulinum, a bacterium found in soil, water and air. Its rule for homemade herbs in oil: refrigerate and use within 4 days, or freeze for the long term.⁶ A 2011 review concluded that freezing is the safest recommendation for home-prepared herbs in oil.⁸ Don’t store herbs in oil at room temperature.¹

ATK notes you can thaw oil cubes and drizzle them over food. That’s fine if you thaw them in the fridge and use them within the 4-day limit.⁶ Just don’t leave a thawed cube of rosemary oil sitting on the counter.

Thawing. Usually you won’t need to. Penn State says not to thaw herbs before adding them to cooked dishes. If you do thaw rosemary, the USDA fact sheet names three safe ways: in the fridge, in cold water, or in the microwave. Warm water isn’t one of them. Freezing at 0°F inactivates bacteria, yeasts and molds, but once thawed they can wake back up,⁷ so handle thawed rosemary like fresh food.

Refreezing. Food thawed in the fridge is safe to refreeze without cooking, though it may lose some quality from moisture lost in thawing.⁷ So refreezing rosemary is a quality question, not a safety one, and freezing in small portions sidesteps it.

Using frozen rosemary

Add it frozen, in the same amount you’d use fresh.¹
Cook with it. Ohio State lists soups, stews, sauces and other cooked dishes as the best uses for frozen herbs. LSU AgCenter groups rosemary with the sturdier herbs that handle heat, so frozen rosemary can go in early in roasts, braises and stews.
Oil cubes suit dishes that start with oil in the pan.
Not as a garnish. Thawed herbs are limp and generally unappealing on a plate.

See cooking with rosemary and rosemary uses.

Freezing or drying rosemary?

Rosemary dries well too. America’s Test Kitchen lists it among the hardier herbs that dry well, and in its fresh-versus-dried tasting, dried rosemary did reasonably well in long-cooked dishes.⁹ In the Sardinian study, freezing held rosemary’s essential oil better than either drying method. Drying gets you a jar that takes no freezer space. Either works. See how to dry rosemary, dried rosemary vs. fresh and how to store rosemary.

Not yet measured

A storage time for frozen rosemary based on flavor or aroma. The one study we found gives oil trends without yield figures.
How long thawed rosemary keeps in the fridge.
How long fresh rosemary keeps in the fridge.
Whether ice cubes, oil or dry-pack freezing keeps rosemary best.

Freezing Herbs, Penn State Extension. extension.psu.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸
Everyone Should Have Herb Ice Cubes in Their Freezer, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩²
Usai et al., Italian Journal of Food Science, 2009. iris.uniss.it · Peer-reviewed ↩ ↩² ↩³
Preserving Herbs: Freezing and Drying (HYG-5360), Ohio State University Extension. ohioline.osu.edu · Reference work ↩ ↩² ↩³
Preserve Smart: Freezing Herbs, Colorado State University Extension. apps.chhs.colostate.edu · Reference work ↩ ↩²
Herbs and Vegetables in Oil (SP 50-701), Oregon State University Extension Service. extension.oregonstate.edu · Reference work ↩ ↩² ↩³
Focus on Freezing, USDA fact sheet (copy hosted by the North Carolina Department of Agriculture). ncagr.gov · Regulator ↩ ↩² ↩³
Nummer et al., Food Protection Trends, 2011. foodprotection.org · Peer-reviewed ↩
Science: Substituting Dried Herbs for Fresh, America’s Test Kitchen. americastestkitchen.com · Publication ↩

Also drawn on

Flavorful Herbs, LSU AgCenter. lsuagcenter.com
When You Should Actually Use Dried Herbs (and Which Ones to Avoid) (Danielle Lapierre, 27 Apr 2022), America's Test Kitchen. americastestkitchen.com

Can You Freeze Rosemary? Methods, Storage Time and What the Research Shows